Ophthalmic surgical instruments and methods of use thereof

ABSTRACT

An ophthalmic surgical instrument includes a housing and a snare operably coupled to the housing. The snare is configured to transition between an insertion configuration and a deployed configuration, in which the snare is sized to encircle lenticular tissue. The ophthalmic surgical instrument is designed to prevent elevation and/or tilting of the lenticular tissue as the snare transitions toward the insertion configuration to divide the lenticular tissue.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/970,145, filed on May 3, 2018, the entire contents of whichare incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to ophthalmic surgical instruments, andmore particularly, to ophthalmic surgical instruments and methods thatfacilitate the fragmentation and removal of a lens from a lens capsule.

Background of Related Art

Cataract surgery and other surgical procedures that treat lenticulartissue, such as, for example, the intraocular lens, are performed bymaking a small incision in the edge of the cornea, which provides accessto the anterior chamber and to the anterior surface of the lens capsule.Afterward, a generally circular incision called a capsulorhexis is madethrough the anterior surface of the lens capsule to provide surgicalaccess to the lens. An ophthalmic surgical instrument may be insertedthrough the capsulorhexis and used to fragment the cataractous lens tofacilitate its removal from the lens capsule. However, duringsegmentation by the surgical instrument, the distal portion of the lensmay be caused to shift undesirably in an upward (i.e., anterior)direction. Such movement may cause trauma to delicate adjacent eyestructures such as the lens zonule, lens capsule or, cornealendothelium.

Accordingly, a continuing need exists in the surgical arts for improvedtools and methods for safely fragmenting and removing a cataractouslens.

SUMMARY

In accordance with an aspect of the present disclosure, an ophthalmicsurgical instrument for severing a lens of an eye is provided andincludes an elongated shaft, and a snare. The elongated shaft includes aproximal end portion and a distal end portion defining an opening. Thedistal end portion is offset from the proximal end portion. The snareextends along the elongated shaft and includes a cutting segmentdisposed adjacent the opening. The cutting segment is configured to movebetween a contracted configuration and a dilated configuration, in whichthe cutting segment assumes a diameter approximating a diameter andshape of a lens. The cutting segment is configured to sever the lensupon moving toward the contracted configuration.

In aspects, the elongated shaft may further include an intermediateportion extending between the proximal and distal end portions. Theintermediate portion may be angled relative to the proximal and distalend portions.

In aspects, the elongated shaft may have a bent proximal segment and abent distal segment. The intermediate portion may extend between thebent proximal and distal segments.

In aspects, the intermediate segment may be curved or linear.

In aspects, the proximal end portion may define a first longitudinalaxis, the distal end portion may define a second longitudinal axis thatis parallel with the first longitudinal axis, and the intermediateportion may define a third longitudinal axis that is non-parallel withrespect to the first and second longitudinal axes.

In aspects, the proximal end portion may define a first longitudinalaxis and the distal end portion may define a second longitudinal axisthat is parallel and out of alignment with the first longitudinal axis.

In aspects, the distal end portion may have a length from about 3.5 mmto about 12 mm.

In aspects, distal end portion may have a length of about 6 mm.

In aspects, the distal end portion may have a bottom portion configuredto be oriented toward a human eye, and an upper portion. The bottomportion may define the opening therein.

In aspects, the upper portion may have a concave inner surfaceoverlapping the looped segment and the opening.

In aspects, the opening may have a length that is less than about halfof a length of the cutting segment when the cutting segment is in thedilated configuration.

In aspects, a majority of the length of the cutting segment may bedisposed proximally and distally of the opening when the cutting segmentis in the dilated configuration.

In accordance with another aspect of the present disclosure, anophthalmic surgical instrument for severing a lens of an eye is providedand includes a handle, an elongated shaft extending distally from thehandle, and a snare coupled to the housing. The elongated shaft includesa distal end portion defining an opening. The distal end portion isangled relative to a proximal portion of the elongated shaft that isdisposed proximally of the distal end portion. The snare is operablycoupled to the housing and includes a looped segment configured to movebetween a contracted configuration and a dilated configuration. In thedilated configuration, the looped segment assumes a diameterapproximating a diameter and shape of a lens. The looped segment isconfigured to sever the lens upon moving toward the contractedconfiguration.

In aspects, the distal end portion may be bent relative to the proximalportion.

In aspects, the proximal portion may include a proximal end portioncoupled to the handle, and an intermediate portion disposed between andinterconnecting the proximal end portion and the distal end portion.

In aspects, the distal end portion may be bent relative to theintermediate portion.

In aspects, the intermediate portion may be bent relative to theproximal end portion in an opposite direction as the distal end portionis bent relative to the intermediate portion.

In aspects, the opening may have a length that is less than about halfof a length of the looped segment when the looped segment is in thedilated configuration.

In aspects, a majority of the length of the looped segment may bedisposed proximally and distally of the opening when the looped segmentis in the dilated configuration.

Further details and aspects of exemplary embodiments of the presentdisclosure are described in more detail below with reference to theappended figures.

As used herein, the terms parallel and perpendicular are understood toinclude relative configurations that are substantially parallel andsubstantially perpendicular up to about + or −25 degrees from trueparallel and true perpendicular.

As used herein, the term “about” means that the numerical value isapproximate and small variations would not significantly affect thepractice of the disclosed embodiments. Where a numerical limitation isused, unless indicated otherwise by the context, “about” means thenumerical value can vary by ±10% and remain within the scope of thedisclosed embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure are described herein withreference to the accompanying drawings, wherein:

FIG. 1A is a top view of an ophthalmic surgical instrument in accordancewith an embodiment of the present disclosure, illustrating a snarethereof in a contracted configuration;

FIG. 1B is a top view of the ophthalmic surgical instrument of FIG. 1A,illustrating the snare in a dilated configuration and a pair ofstabilization elements in an open configuration;

FIG. 2A is a side cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the contractedconfiguration and the stabilization elements in the closedconfiguration;

FIG. 2B is a side cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the dilatedconfiguration and the stabilization elements in the open configuration;

FIG. 3A is a top cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the contractedconfiguration and the stabilization elements in the closedconfiguration;

FIG. 3B is a top cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the dilatedconfiguration and the stabilization elements in the open configuration;

FIG. 4A is a side view of another embodiment of an ophthalmic surgicalinstrument, illustrating a snare thereof in a contracted configuration;

FIG. 4B is a side view of the ophthalmic surgical instrument of FIG. 4A,illustrating the snare in a dilated configuration;

FIG. 5A is a side view of yet another embodiment of an ophthalmicsurgical instrument, illustrating a snare thereof in a contractedconfiguration;

FIG. 5B is a side view of the ophthalmic surgical instrument of FIG. 5A,illustrating the snare in a dilated configuration; and

FIG. 6 is a side view of yet another embodiment of an ophthalmicsurgical instrument, illustrating a snare thereof in a contractedconfiguration.

DETAILED DESCRIPTION

Embodiments of the presently disclosed ophthalmic surgical instrumentsare described in detail with reference to the drawings, in which likereference numerals designate identical or corresponding elements in eachof the several views. As used herein and as is traditional, the term“distal” will refer to that portion of the ophthalmic surgicalinstrument which is further from the user (i.e., closer to the eye)while the term “proximal” will refer to that portion of the ophthalmicsurgical instrument which is closer to the user (i.e., further from theeye).

The present disclosure provides embodiments of an ophthalmic surgicalinstrument used to fragment cataractous lenticular tissue prior to itsremoval from a lens capsule. The ophthalmic surgical instrument includesa handle portion, a snare for enclosing and severing the lenticulartissue, and a pair of stabilization elements that are selectivelyextendable outwardly relative to the snare during actuation of thesnare. The stabilization elements may be any suitable structure thatextends outwardly from the distal end or from opposite sides of thesnare to overlay opposing sides of the lenticular tissue during itsdivision by the snare. As the snare is contracted about the lenticulartissue, the stabilization elements resist anterior shifting (i.e.,upward shifting) of the lenticular tissue, which may otherwise occur dueto the proximally-oriented force exerted on the lenticular tissue duringcontraction of the snare. In some embodiments, the ophthalmic surgicalinstrument is constructed so that a distally-extending cannula thereofacts as the stabilization element. These and other features andadvantages of the various embodiments of the disclosed ophthalmicsurgical instruments will be described below.

With reference to FIGS. 1A-3C, an exemplary embodiment of an ophthalmicsurgical instrument is illustrated and is generally designated 100. Theophthalmic surgical instrument 100 generally includes a housing 110, asnare 112 for severing lenticular tissue, and a pair of stabilizationelements, such as, for example, elongated arms 120, 122 that selectivelyexpand from a closed or collapsed configuration (FIGS. 1A, 2A, 3A) to anopen or expanded configuration (FIGS. 1B, 2B, 3B).

The housing 110 of the ophthalmic surgical instrument 100 has a handlebody 114 and first and second levers 116 a, 116 b slidably coupled tothe handle body 114. The handle body 114 may be ergonomic and have anelongated configuration. In embodiments, the handle body 114 may assumeany suitable shape, such as, for example, rounded, planar, rectangular,or the like. The handle body 114 has a tapered distal end portion 118dimensioned to assist in positioning the ophthalmic surgical instrument100 adjacent eye structure. The levers 116 a, 116 b may be configured assliders, buttons, triggers, or the like. In embodiments, the housing 110may include a cannulated member, such as, for example, a hollow shaft(not shown), extending distally from the distal end portion 118 of thehandle body 114 to facilitate entry of the ophthalmic surgicalinstrument 100 through a standard corneal incision.

The snare 112 of the ophthalmic surgical instrument 100 is operablycoupled to the first lever 116 a of the housing 110 and includes a firstend portion 112 a and a second end portion 112 b (FIGS. 2A and 2B). Thefirst end portion 112 a of the snare 112 is movable relative to thehousing 110, while the second end portion 112 b of the snare 112 isfixed relative to the housing 110. In particular, the first end portion112 a of the snare 112 is coupled to the first lever 116 a of thehousing via a first actuator rod 124, such that movement of the firstlever 116 a moves the first end portion 112 a of the snare 112, and thesecond end portion 112 b of the snare 112 is fixed to an inner tubularstructure 126 (FIGS. 3A and 3B) formed in the distal end portion 118 ofthe handle body 114. It is contemplated that the second end portion 112b of the snare 112 may be fixed to the inner tubular structure 126 ofthe handle body 114 by crimping, welding, adhesives, mechanicalinterlocks, or any other suitable structure or method.

With reference to FIGS. 2A and 2B, the snare 112 has a looped segment128 disposed at least partially outside of the housing 110. The loopedsegment 128 of the snare 112 is transitionable, via an actuation of thefirst lever 116 a, between an insertion or contracted configuration, asshown in FIGS. 1A, 2A, and 3A, and a deployed or dilated configuration,as shown in FIGS. 1B, 2B, and 3B. For example, a proximal retraction ofthe first lever 116 a moves the first end portion 112 a of the snare 112proximally away from the second end portion 112 b of the snare 112,thereby reducing the diameter of the looped segment 128. In contrast, adistal advancement of the first lever 116 a moves the first end portion112 a of the snare 112 distally toward the second end portion 112 b ofthe snare 112, thereby increasing the diameter of the looped segment 128of the snare 112. The looped segment 128 has a predefined shapedimensioned to closely encircle a lens when the looped segment 128 is inthe dilated configuration.

In embodiments, at least the looped segment 128 of the snare 112 may bea metal or polymer wire, tether, strap, belt, or the like, with anysuitable cross-section configuration configured to sever lenticulartissue during contraction of the looped segment 128 about the lenticulartissue.

For an exemplary description of further features of the snare 112 andthe mechanism of its operation, reference may be made to U.S. Pat. No.9,775,743, filed on Sep. 17, 2014, the entire contents of which beingincorporated by reference herein.

With continued reference to FIGS. 1B and 2A-3B, the stabilizationelements or arms 120, 122 of the ophthalmic surgical instrument 100 aredisposed on opposite sides of a longitudinal axis “X” defined by thesnare 112. The arms 120, 122 are configured to move from the closedconfiguration (FIGS. 1A, 2A, 3A) to the open configuration (FIGS. 1B,2B, 3B) to maintain lenticular tissue in its current location, typicallybut not always within its lens capsule, as will be described. Inembodiments, the arms 120, 122 may be configured to move independentlyof one another. The arms 120, 122 are illustrated as being linear, butit is contemplated that the arms 120, 122 may assume any suitable shape,such as, for example, wing-shaped, disc-shaped, plate-like, orpolygonal.

The arms 120, 122 may be resiliently-biased toward the openconfiguration by a biasing member, such as, for example, a coil spring130, disposed therebetween. As such, upon moving the arms 120, 122distally out of the handle body 114 or the hollow shaft (not shown) ofthe housing 110, the arms 120, 122 automatically expand outwardlyrelative to one another. The arms 120, 122 each have a proximal endportion 120 a, 122 a pivotably coupled to a hub 132, and a distal endportion 120 b, 122 b. In other embodiments, instead of being pivotable,the arms 120, 122 may be configured to shift laterally outward from thecollapsed configuration to the expanded configuration.

The hub 132 couples the arms 120, 122 to the second lever 116 b of thehousing 110. In particular, the housing 110 has a second actuator rod134 interconnecting the hub 132 and the second lever 116 b. Upon slidingthe second lever 116 b relative to the handle body 114, the secondactuator rod 134 transfers the sliding motion to the hub 132 to axiallymove the arms 120, 122 along the longitudinal axis “X” of the snare 112relative to the handle body 114 between a proximal position and a distalposition. In the proximal position, the arms 120, 122 are concealedwithin the inner tubular structure 126 of the handle body 110 or thehollow shaft when the hollow shaft is used. With the arms 120, 122disposed within the housing 110, the inner tubular structure 126 of thehandle body 119 (or the hollow shaft when used) maintains the arms 120,122 in the collapsed configuration, in which the arms 120, 122 areparallel with one another and the longitudinal axis “X” of the snare112, therefore assuming a reduced profile. Upon moving the arms 120, 122toward the distal position, the arms 120, 122 move distally out of thehousing 110 (the handle body 114 and/or the hollow shaft when used)allowing the outwardly-oriented bias of the biasing member 130 totransition the arms 120, 122 toward the expanded configuration. Inembodiments, rather than automatically moving toward the expandedconfiguration upon exiting the housing 110, the arms 120, 122 may beexpanded manually via a drive mechanism (not shown).

As shown in FIGS. 1B and 3B, in the expanded configuration, the arms120, 122 flare outwardly from opposite sides of the snare 112 to definean angle α between the arms 120, 122. In embodiments, the angle α may bebetween about 0.1 degrees and about 180 degrees. In embodiments, theangle α may be between about 10 degrees and about 90 degrees.

The arms 120, 122 together define and reside in a horizontal plane, andthe expanded looped segment 128 of the snare 112 defines and resides ina vertical plane that is aligned with the longitudinal axis “X” of thesnare 112. The arms 120, 122 remain the horizontal plane throughouttheir movement between the collapsed and expanded configurations. Thearms 120, 122 are parallel with the longitudinal axis “X” of the snare112 while the horizontal plane of the arms 120, 122 is perpendicularrelative to the vertical plane of the looped segment 128 of the snare112.

In embodiments, the arms 120, 122 may be axially movable in a directionperpendicular to the horizontal plane of the looped segment 128 toadjust a vertical position of the arms 120, 122 relative to the housing110 as well as lenticular tissue. For example, the housing 110 mayfurther include a third lever (not shown) coupled to the hub 132 formoving the arms 120, 122 vertically relative to the housing 110.

As best shown in FIGS. 2A and 2B, each of the arms 120, 122 has aposterior tissue-contacting surface 136. The posterior tissue-contactingsurface 136 of the arms 120, 122 may define an arcuate recess 138therein dimensioned to conform to an anterior surface of a lens of aneye. As such, upon deploying the arms 120, 122 over a lens, theposterior tissue-contacting surface 136 of each of the arms 120, 122cups the anterior surface of the lens, thereby providing increasedsurface contact between the arms 120, 122 and the lens. It iscontemplated that the posterior tissue-contacting surface 136 may have acoating or liner of pliable material, such as an elastomer to helpprotect vulnerable structures in the eye.

In operation, a small incision in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface of acataractous lens of a patient's eye “E” (FIG. 3B). A capsulorhexis ismade through the anterior surface of a lens capsule of the patient's eye“E,” thereby providing surgical access to the cataractous lens “L.” Withthe arms 120, 122 of the ophthalmic surgical instrument 100 disposed inthe proximal position within the housing 110, and the snare 112 in theinsertion configuration, as shown in FIGS. 2A and 3A, the hollow shaftof the housing 110 is inserted through the corneal incision and thecapsulorhexis to position the looped segment 128 of the snare 112adjacent the anterior surface of the lens “L.” Once in position, thefirst lever 116 a is advanced to move the first end portion 112 a of thesnare 112 distally, thereby transitioning the looped segment 128 fromthe insertion configuration to the deployed configuration, as shown inFIG. 2B. With the looped segment 128 in the deployed configuration, thesnare 112 is rotated about its longitudinal axis “X” (e.g., via rotationof the entire ophthalmic surgical instrument 100 or via a rotationmechanism (not shown) coupled to the snare 112) to rotate the loopedsegment 128 circumferentially about the lens to encircle the lens andposition the looped segment 128 so that the vertical plane defined bythe looped segment 128 bisects the lens.

With the looped segment 128 of the snare 112 in the selected positionnoted above, the second lever 116 b of the housing 110 may be advancedto move the arms 120, 122 from the proximal position to the distalposition. As noted above, as the arms 120, 122 move to the distalposition, the arms 120, 122 automatically transition from the closedconfiguration to the open configuration, as shown in FIGS. 1B and 3B.More specifically, the arms 120, 122 move distally along the anteriorsurface of the lens “L” while also expanding relative to one another andthe longitudinal axis “X” of the snare 112 to position the posteriortissue-contacting surface 136 (FIG. 2B) of each of the arms 120, 122over lateral side portions of the anterior surface of the lens “L.”

With the arms 120, 122 overlaying and in contact with the anteriorsurface of the lens “L,” the first lever 116 a may then be retracted totransition the looped segment 128 from the dilated configuration to thecontracted configuration, dividing the lens “L” into two hemisphericalsections. During constriction of the looped segment 128 about the lens“L,” the looped segment 128 may exert a proximally-oriented and/oranteriorly oriented force on a distal pole “P” of the lens “L.” However,since the arms 120, 122 are in position over the lens “L,” the arms 120,122 resist and/or prevent the distal pole “P” of the lens “L” fromshifting proximally out of the lens capsule notwithstanding theproximally-oriented force exerted thereon by the snare 112.

After one or more fragmentations of the lens “L” by the ophthalmicsurgical instrument 100, the fragmented sections of the cataractous lens“L” may then be removed from the eye “E” using any suitable mechanism,such as, for example, an ultrasonic aspirator.

In some embodiments, the snare 112 and/or the arms 120, 122 may bemechanically powered through an electric motor, a pneumatic powersource, a hydraulic power source, magnets, or the like. It is alsocontemplated that the ophthalmic surgical instrument 100 may beincorporated into a robotic surgical system.

With reference to FIGS. 4A and 4B, another embodiment of an ophthalmicsurgical instrument 200 is illustrated, similar to the ophthalmicsurgical instrument 100 described above. Due to the similarities betweenthe ophthalmic surgical instrument 200 of the present embodiment and theophthalmic surgical instrument 100 described above, only those elementsof the ophthalmic surgical instrument 200 deemed necessary to elucidatethe differences from ophthalmic surgical instrument 100 described abovewill be described in detail.

The ophthalmic surgical instrument 200 generally includes a housing 210and a snare 212 for severing lenticular tissue. The housing 210 of theophthalmic surgical instrument 200 has a handle body 214 and acannulated body, such as, for example, a hollow shaft 226 extendingdistally from the handle body 214. The hollow shaft 226 is dimensionedfor passage through a corneal incision and has a proximal end 226 aintegrally formed with or attached to the handle body 214.

The snare 212 of the ophthalmic surgical instrument 200 includes a firstend portion 212 a and a second end portion 212 b. The first end portion212 a of the snare 212 is movable relative to and within the hollowshaft 226 of the housing 210 via an actuation mechanism (not shown),while the second end portion 212 b of the snare 212 is fixed relative tothe housing 210. It is contemplated that the first end portion 212 a ofthe snare 212 may be axially movable within the hollow shaft 226 via anysuitable actuation mechanism, such as, for example, manual actuation orany suitable motorized actuation mechanism. The second end portion 212 bof the snare 212 may be fixed to an inner surface of the hollow shaft226 by crimping, welding, adhesives, mechanical interlocks, or any othersuitable structure or method.

The snare 212 has a looped segment 228 disposed protruding out of adistal end 226 b of the hollow shaft 226. The looped segment 228 of thesnare 212 is transitionable, via axial movement of the first end portion212 a of the snare 212, between an insertion or contractedconfiguration, as shown in FIG. 4A, and a deployed or dilatedconfiguration, as shown in FIG. 4B. For example, a proximal retractionof a lever (not shown) of the housing 210 moves the first end portion212 a of the snare 212 proximally away from the second end portion 212 bof the snare 212, thereby reducing the diameter of the looped segment228. In contrast, a distal advancement of the lever moves the first endportion 212 a of the snare 212 distally toward the second end portion212 b of the snare 212, thereby increasing the diameter of the loopedsegment 228 of the snare 212. The looped segment 228 has a predefinedshape dimensioned to closely encircle a lens when the looped segment 228is in the dilated configuration.

The looped segment 228 of the snare 212 differs from the looped segment128 of the snare 112 of the ophthalmic surgical instrument 100 of FIGS.1A-3B in that a majority of the looped segment 228 overlaps with thehousing 210 (e.g., the hollow shaft 226) rather than a majority of thelooped segment 228 being disposed distally of the housing 210. Thelooped segment 228 has a proximal section 228 a having a predefinedcurvature, and a distal section 228 b having a predefined curvature. Thedistal section 228 b of the looped segment 228 is disposed distally ofthe distal end 226 of the hollow shaft 226, and the proximal section 228a of the looped segment 228 is disposed below the hollow shaft 226 andproximally of the distal end 226 b of the hollow shaft 226.

The looped segment 228 further includes a pre-bent section 228 cextending from the second end portion 212 b of the snare 212. Thepre-bent section 228 c is disposed distally and outside of the housing210 and has a smaller radius of curvature relative to the proximal anddistal sections 228 a, 228 b of the looped segment 228 to position theproximal section 228 a of the looped segment 228 proximally of andunderneath the distal end 226 of the hollow shaft 226 of the housing210. The proximal section 228 a, the distal section 228 b, and thepre-bent section 228 c of the looped segment 228 may be fabricated fromthe same material or different materials. For example, the pre-bentsection 228 c may be fabricated from a less flexible material than theproximal and distal sections 228 a, 228 b of the looped segment 228 toensure that a majority of the looped segment 228 overlaps with thehollow shaft 226 throughout the transition of the looped segment 228between the contracted and dilated configurations.

The looped segment 228 defines a length “L” parallel with a centrallongitudinal axis “A” defined by the hollow shaft 226. The proximalsection 228 a of the looped segment 228 has a length “L1,” which isapproximately ½ or more of the overall length “L” of the looped segment228, and the distal section 228 b of the looped segment 228 has a length“L2,” which is less than ½ of the overall length of the looped segment228. In embodiments, the length “L1” of the proximal section 228 a ofthe looped segment 228 is approximately ¾ of the overall length “L” ofthe looped segment 228, and the distal section 228 b of the loopedsegment 228 has a length “L2,” which is approximately ¼ of the overalllength “L” of the looped segment 228. In this way, during use of theophthalmic surgical instrument 200, a majority of the looped segment 228overlaps with the housing 210 (e.g., the hollow shaft 226), such thatthe housing 210 is configured to rest on lenticular tissue during itsfragmentation to prevent upward movement thereof during constriction ofthe looped segment 228.

The looped segment 228 is fabricated from shape memory materials, suchas, for example, a nickel-titanium alloy to allow the looped segment 228to move to its predefined, dilated configuration. Other shape memorymaterials, such as shape memory plastics are also contemplated. In otherembodiments, the looped segment 228 may be fabricated from any suitablebiocompatible material including, but not limited to, stainless steel,titanium, silicone, polyimide, polyether block amide, nylon,polycarbonate, or combinations thereof.

In operation, a small incision in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface of acataractous lens of a patient's eye. A capsulorhexis is made through theanterior surface of a lens capsule of the patient's eye providingsurgical access to the cataractous lens. With the snare 212 of theophthalmic surgical instrument 200 in the insertion configuration, asshown in FIG. 4A, the hollow shaft 226 of the housing 210 is insertedthrough the corneal incision and the capsulorhexis to position a distalend portion of the hollow shaft 226 in an overlapping arrangement withthe anterior surface of the lens, and position the looped segment 228 ofthe snare 212 adjacent the anterior surface of the lens.

Once the looped segment 228 is in the appropriate position, the firstend portion 212 a of the snare 212 is advanced distally, therebytransitioning the looped segment 228 from the insertion configuration tothe deployed configuration, as shown in FIG. 4B. With the looped segment228 in the deployed configuration, the snare 212 is rotated about itslongitudinal axis “A” (e.g., via rotation of the entire ophthalmicsurgical instrument 200 or via a rotation mechanism (not shown)) torotate the looped segment 228 circumferentially about the lens toencircle the lens and position the looped segment 228 relative to thelens so that the plane defined by the looped segment 228 bisects thelens. Upon rotating the snare 212 to the selected position, the distalend portion of the hollow shaft 226 overlaps with the anterior surfaceof the lens and a majority of the looped segment 228 of the snare 212.

With the looped segment 228 of the snare 212 disposed about the lens,and the distal end portion of the hollow shaft 226 overlaying and incontact with the anterior surface of the lens, the looped segment 228 istransitioned from the dilated configuration to the contractedconfiguration, dividing the lens into two hemispherical sections. Duringconstriction of the looped segment 228 about the lens, the loopedsegment 228 may exert a proximally-oriented and/or anteriorly-orientedforce on a distal pole of the lens. However, since the distal endportion of the hollow shaft 226 is in position over the lens, the hollowshaft 226 resists and/or prevents elevation and/or tilting of the distalpole of the lens notwithstanding the proximally-oriented force exertedthereon by the closing snare 212.

After one or more fragmentations of the lens by the ophthalmic surgicalinstrument 200, the fragmented sections of the cataractous lens may thenbe removed from the eye using any suitable mechanism, such as, forexample, an ultrasonic aspirator.

With reference to FIGS. 5A and 5B, another embodiment of an ophthalmicsurgical instrument 300 is illustrated, similar to the ophthalmicsurgical instrument 200 described above. Due to the similarities betweenthe ophthalmic surgical instrument 300 of the present embodiment and theophthalmic surgical instrument 200 described above, only those elementsof the ophthalmic surgical instrument 300 deemed necessary to elucidatethe differences from ophthalmic surgical instrument 200 described abovewill be described in detail.

The ophthalmic surgical instrument 300 generally includes a housing 310and a snare 312 operably coupled to the housing 310 for severinglenticular tissue. The housing 310 of the ophthalmic surgical instrument300 has a handle body 314 and a cannulated body, such as, for example, ahollow shaft 326 extending distally from the handle body 314. The hollowshaft 326 is dimensioned for passage through a corneal incision and hasa proximal end 326 a integrally formed with or attached to the handlebody 314, and a closed distal end 326 b. In embodiments, the distal end326 b of the hollow shaft 326 may be open. The hollow shaft 326 definesa central longitudinal axis “B” and defines a lateral opening 330 in alateral side surface 332 thereof. The lateral opening 330 is laterallyoffset from the central longitudinal axis “B” and defines an axis “C”therethrough that is perpendicular to the central longitudinal axis “A”of the hollow shaft 326. The lateral opening 330 may be any suitableshape, such as, for example, circular, elongated, square, or the like.

The snare 312 of the ophthalmic surgical instrument 300 includes a firstend portion 312 a and a second end portion 312 b. The first end portion312 a of the snare 312 is movable relative to and within the hollowshaft 326 of the housing 310 via an actuation mechanism (not shown),similar to the actuation mechanism described above, while the second endportion 312 b of the snare 312 is fixed relative to the housing 310. Thesecond end portion 312 b of the snare 312 may be fixed to an innersurface of the hollow shaft 226 by crimping, welding, adhesives,mechanical interlocks, or any other suitable structure or method. Inother embodiments, both the first and second end portions 312 a, 312 bmay be axially movable.

The snare 312 has a looped segment 328 protruding out of the lateralopening 330 in the lateral side 332 of the hollow shaft 226. The loopedsegment 328 of the snare 312 is transitionable, via axial movement ofthe first end portion 312 a of the snare 312, between an insertion orcontracted configuration, as shown in FIG. 5A, and a deployed or dilatedconfiguration, as shown in FIG. 5B. For example, a proximal retractionof a lever (not shown) of the housing 310 moves the first end portion312 a of the snare 312 proximally away from the second end portion 312 bof the snare 312, thereby reducing the diameter of the looped segment328. In contrast, a distal advancement of the lever moves the first endportion 312 a of the snare 312 distally toward the second end portion312 b of the snare 312, thereby increasing the diameter of the loopedsegment 328 of the snare 312. The looped segment 328 has a predefinedshape dimensioned to closely encircle a lens when the looped segment 328is in the dilated configuration. In embodiments, both the first andsecond end portions 312 a, 312 b of the snare 312 may be movable tocontract or dilate the looped segment 328.

The looped segment 328 defines a length “L” parallel with a centrallongitudinal axis “B” defined by the hollow shaft 326. A majority of thelength “L” of the looped segment 328 is in side-by-side, parallelrelation with the lateral side 332 of the hollow shaft 326. Further, amajority of the looped segment 328 (i.e., at least half) is disposedproximally of the distal end 326 b of the hollow shaft 326. In this way,during use of the ophthalmic surgical instrument 300, the hollow shaft326 hangs over a majority of the looped segment 328, such that thehollow shaft 326 sits on a lens during lens fragmentation to preventupward movement of the lens as the looped segment 328 is constrictedthereabout.

The looped segment 328 includes a proximal section 328 a disposedproximally of the lateral opening 330, and a distal section 328 bdisposed distally of the lateral opening 330. Both the proximal anddistal sections 328 a, 328 b of the looped segment 328 are disposedproximally of the distal end 326 b of the hollow shaft 326 when thelooped segment 328 is in the contracted configuration, as shown in FIG.5A. When the looped segment 328 is in the dilated configuration, theproximal section 328 a of the looped segment 328 is disposed proximallyof the distal end 326 b of the hollow shaft 326, whereas a majority,e.g., at least about half, of the distal segment 328 b is disposedproximally of the distal end 326 b of the hollow shaft 326. As such, amajority of the looped segment 328 is disposed alongside the lateralside 332 of the hollow shaft 326 throughout the transition of the loopedsegment 328 between the contracted and dilated configurations.

The looped segment 328 is fabricated from shape memory materials, suchas, for example, a nickel-titanium alloy to allow the looped segment 328to move to its predefined, dilated configuration. Other shape memorymaterials, such as shape memory plastics are also contemplated. In otherembodiments, the looped segment 328 may be fabricated from any suitablebiocompatible material including, but not limited to, stainless steel,titanium, silicone, polyimide, polyether block amide, nylon,polycarbonate, or combinations thereof.

In operation, a small incision in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface of acataractous lens of a patient's eye. A capsulorhexis is made through theanterior surface of a lens capsule of the patient's eye providingsurgical access to the cataractous lens. With the snare 312 of theophthalmic surgical instrument 300 in the contracted configuration, asshown in FIG. 5A, the hollow shaft 326 of the housing 310 is insertedthrough the corneal incision and the capsulorhexis to position a distalend portion of the hollow shaft 326 in an overlapping arrangement withthe anterior surface of the lens, and position the looped segment 328 ofthe snare 312 adjacent the anterior surface of the lens.

Once the looped segment 328 is in the appropriate position, the firstend portion 312 a of the snare 312 is advanced distally, therebytransitioning the looped segment 328 from the contracted configurationto the dilated configuration, as shown in FIG. 5B. With the loopedsegment 328 in the deployed configuration, the snare 312 is rotatedabout its longitudinal axis “B” (e.g., via rotation of the entireophthalmic surgical instrument 300 or via a rotation mechanism (notshown)) to rotate the looped segment 328 circumferentially about thelens to encircle the lens and position the looped segment 328 relativeto the lens so that the plane defined by the looped segment 328 bisectsthe lens. Upon rotating the snare 312 to the selected position, the axis“C” defined through the lateral opening 330 in the hollow shaft 326extends perpendicularly through a center of the eye, whereby the hollowshaft 326 overlaps with the anterior surface of the lens and a majorityof the looped segment 328 of the snare 312.

With the looped segment 328 of the snare 312 disposed about the lens,and the hollow shaft 326 overlaying and in contact with the anteriorsurface of the lens, the looped segment 328 is transitioned from thedilated configuration to the contracted configuration, dividing the lensinto two hemispherical sections. During contraction of the loopedsegment 328 about the lens, the looped segment 328 may exert aproximally-oriented force on a distal pole of the lens. However, sincethe hollow shaft 326 is in position over the lens, the hollow shaft 326resists and/or prevents elevation and/or tilting of the distal pole ofthe lens notwithstanding the proximally-oriented force exerted thereonby the closing snare 312.

After one or more fragmentations of the lens by the ophthalmic surgicalinstrument 300, the fragmented sections of the cataractous lens may thenbe removed from the eye using any suitable mechanism, such as, forexample, an ultrasonic aspirator.

With reference to FIG. 6, another embodiment of an ophthalmic surgicalinstrument 400 is illustrated, similar to the ophthalmic surgicalinstrument 300 described above. Due to the similarities between theophthalmic surgical instrument 400 of the present embodiment and theophthalmic surgical instrument 300 described above, only those elementsof the ophthalmic surgical instrument 400 deemed necessary to elucidatethe differences from ophthalmic surgical instrument 300 described abovewill be described in detail.

The ophthalmic surgical instrument 400 generally includes a housing (notexplicitly shown), an elongated shaft 426 extending distally from thehousing, and a snare 412 for severing lenticular tissue. The elongatedshaft 426 is dimensioned for passage through a corneal incision “E” andhas a proximal portion 425 and a distal end portion 426 b formed with orotherwise coupled to the proximal portion 425. The proximal portion 425may include a proximal end portion 426 a integrally formed with orattached to the handle housing and an intermediate portion 426 c. Inaspects, the elongated shaft 426 may be devoid of any intermediateportion, such that the distal end portion 426 b bends directly from theproximal end portion 426 a. In embodiments, the distal tip of theelongated shaft 426 may be open or closed.

The proximal end portion 426 a of the elongated shaft 426 may have alinear configuration and define a central longitudinal axis “X1,” andthe distal end portion 426 b may also be linear and define a centrallongitudinal axis “X2,” that is offset from and parallel with thecentral longitudinal axis “X1” of the proximal end portion 426 a. Thedistal end portion 426 b is angled relative to the proximal portion 425so that upon entry of the distal end portion 426 b into a cornealincision “E,” the distal end portion 426 b will be positioned flush withthe anterior surface “AS” of the lens “L” rather than at an angle, whichwould otherwise occur if the distal end portion 426 b were coaxial withthe proximal portion 425. In aspects, the distal end portion 426 b orthe proximal end portion 426 a may assume any suitable configuration.For example, the distal end portion 426 b may be curved along its length(e.g., to match a curvature of a lens).

The intermediate portion 426 c of the elongated shaft 426 extendsbetween the proximal and distal end portions 426 a, 426 b, and is angledrelative to the proximal and distal end portions 426 a, 426 b. Theintermediate portion 426 c may extend between a bent proximal segment432 of the elongated shaft 426 and a bent distal segment 434 of theelongated shaft 426. The intermediate portion 426 c may have a length ofabout 2 mm between opposite ends “E” and “F” thereof. The intermediateportion 426 c has a linear configuration and defines a third centrallongitudinal axis “X3” that is non-parallel relative to the first andsecond central longitudinal axes “X1,” “X2.” In aspects, the centrallongitudinal axis “X2” of the intermediate portion 426 c may be anobtuse angle (e.g., from about 100 degrees to about 170 degrees), anacute angle (e.g., from 10 degrees to about 80 degrees), or a rightangle (e.g., about 90 degrees) relative to the first and second centrallongitudinal axes “X1,” “X2.”

In aspects, instead of the intermediate portion 426 c being linear, theintermediate portion 426 c may be curved along its length, bent atvarious points along its length, or assume any suitable configurationthat positions the distal end portion 426 b of the elongated shaft 426on a different plane from the proximal portion 425. In aspects, theintermediate portion 426 c may be flexible and/or transitionable betweenan angled position relative to the proximal and distal end portions 426a, 426 b, and a coaxial configuration therewith. In aspects, theintermediate portion 426 c or various portions of the elongated shaft426 may be manually transitionable or fabricated from shape memorymaterial that allows the elongated shaft 426 to transition from anotherwise coaxial configuration into the angled configuration asillustrated.

The distal end portion 426 b of the elongated shaft 426 has a lengthfrom about 3.5 mm to about 12 mm and, in some aspects, the distal endportion 426 b may have a length of about 6 mm or about half the diameterof a cornea measured between points “A” and “B.” The distal end portion426 b has a bottom portion 436 configured to be oriented toward a humaneye, and an upper portion 438 disposed on an opposite side of the distalend portion 426 b. The bottom portion 436 defines an opening 430 thereinthat is disposed at about a midpoint between opposite ends “C,” “D” ofthe distal end portion 426 b. The opening 430 may be configured as anarcuate cutout in the bottom portion 436 of the distal end portion 426b. In aspects, the opening 430 may assume any suitable configuration.The upper portion 438 of the distal end portion 426 b has an innersurface 440 and an opposed outer surface 442. The inner surface 440 mayform a concave depression 444 and the outer surface 442 may form aconvex protuberance 446. The concave depression 444 and the convexprotuberance 446 overlap the opening 430. The concave depression 444provides for more space into which the snare 412 may retract, as will bedescribed.

The snare 412 of the ophthalmic surgical instrument 400 is movablerelative to and within the elongated shaft 426 via an actuationmechanism (not shown), similar to the actuation mechanism describedabove. The snare 412 has a cutting segment, such as, for example, alooped segment 428 configured to protrude out of the opening 430 whenthe looped segment 428 is in a dilated configuration. It is contemplatedthat due to the additional space provided by the concave depression 444in the distal end portion 426 b of the elongated shaft 426, the loopedsegment 428 of the snare 412 may be entirely or substantially receivedin the elongated shaft 426 when in the contracted configuration. It iscontemplated that a distance of about 0.5 mm may be defined between apoint “H” of the upper portion 442 and a point “G” of the convexprotuberance 446. As such, the looped segment 428 may have about 0.5 mmadditional space into which it may retract.

The looped segment 428 defines a length parallel with the centrallongitudinal axis “X2” defined by the distal end portion 426 b of theelongated shaft 426. Due to the length of the opening 430 of theelongated shaft 426 being substantially smaller than the length of thelooped segment 428 in the dilated configuration, a majority of thelength of the looped segment 428 overlaps with the bottom portion 436 ofthe elongated shaft 426 when the looped segment 428 is in the dilatedconfiguration. In this way, during use of the ophthalmic surgicalinstrument 400, the bottom portion 436 of the elongated shaft 426 hangsover a majority of the looped segment 428, such that the elongated shaft426 sits on a lens “L” during lens fragmentation to prevent upwardmovement of the lens “L” as the looped segment 428 is constrictedthereabout.

In operation, a small incision “E” in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface “AS” of acataractous lens “L” of a patient's eye. As is typical, the incision “E”is anterior to an anterior surface “AS” of the lens “L.” A capsulorhexisis made through the anterior surface of a lens capsule of the patient'seye providing surgical access to the cataractous lens “L.”

With the snare 412 of the ophthalmic surgical instrument 400 in thecontracted configuration, as shown in FIG. 6, the elongated shaft 426 isinserted through the corneal incision “E” and the capsulorhexis toposition the distal end portion 426 b of the elongated shaft 426 in anoverlapping arrangement with the anterior surface “AS” of the lens “L,”and position the looped segment 428 of the snare 412 anterior to acentral location of the anterior surface “AS” of the lens “L.” Due tothe distal end portion 426 b being angled relative to the proximalportion 425, the distal end portion 426 b is naturally positioned inflush engagement with the anterior surface “AS” of the lens “L” whilethe proximal portion 425 extends through the incision “E.”

Once the looped segment 428 is in the appropriate position, the loopedsegment 428 is transitioned from the contracted configuration to thedilated configuration, similar to that shown in FIG. 5B. With the loopedsegment 428 in the deployed configuration, the looped segment 428 of thesnare 412 naturally encircles the lens, due to the shape memory materialfrom which the looped segment 428 is fabricated, so that the planedefined by the looped segment 428 bisects the lens. With the loopedsegment 428 of the snare 412 disposed about the lens “L,” and theelongated shaft 426 overlaying and contacting the anterior surface “AS”of the lens “L,” the looped segment 428 is transitioned from the dilatedconfiguration to the contracted configuration, dividing the lens intotwo hemispherical sections.

During contraction of the looped segment 428 about the lens “L,” thelooped segment 428 may exert a proximally-oriented force on the lens“L.” However, since the distal end portion 426 b of the elongated shaft426 is in position over the lens “L,” the elongated shaft 426 resistsand/or prevents elevation and/or tilting of the lens “L” notwithstandingthe proximally/anteriorly-oriented force exerted thereon by the closingsnare 412. If the proximal and distal end portions 426 a, 426 b of theelongated shaft 426 were coaxial instead of being disposed on differentplanes, the distal end portion 426 b would be set at an upward anglerelative to the lens “L,” which would result in an unevenly dispersedforce being exerted on the lens “L” during contraction of the loopedsegment 428 about the lens “L.”

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications of variousembodiments. Those skilled in the art will envision other modificationswithin the scope and spirit of the claims appended thereto.

The invention claimed is:
 1. An ophthalmic surgical instrument forsevering a lens of an eye, comprising: an elongated shaft including: aproximal end portion; and a distal end portion defining an opening, thedistal end portion being offset from the proximal end portion; and asnare extending along the elongated shaft and including a cuttingsegment disposed adjacent the opening and configured to move between acontracted configuration and a dilated configuration, in which thecutting segment assumes a diameter approximating a diameter and shape ofa lens, wherein the cutting segment is configured to sever the lens uponmoving toward the contracted configuration, wherein the elongated shaftfurther includes an intermediate portion extending between the proximaland distal end portions, the intermediate portion being angled relativeto the proximal and distal end portions, wherein the proximal endportion defines a first longitudinal axis, the distal end portiondefines a second longitudinal axis that is parallel with the firstlongitudinal axis.
 2. The ophthalmic surgical instrument according toclaim 1, wherein the elongated shaft has a bent proximal segment and abent distal segment, the intermediate portion extending between the bentproximal and distal segments.
 3. The ophthalmic surgical instrumentaccording to claim 1, wherein the intermediate segment is curved orlinear.
 4. The ophthalmic surgical instrument according to claim 1,wherein the proximal end portion defines a first longitudinal axis andthe distal end portion defines a second longitudinal axis that isparallel and out of alignment with the first longitudinal axis.
 5. Theophthalmic surgical instrument according to claim 1, wherein the distalend portion has a length from about 3.5 mm to about 12 mm.
 6. Theophthalmic surgical instrument according to claim 5, wherein the distalend portion has a length of about 6 mm.
 7. The ophthalmic surgicalinstrument according to claim 1, wherein the distal end portion has abottom portion configured to be oriented toward a human eye, and anupper portion, the bottom portion defining the opening therein.
 8. Theophthalmic surgical instrument according to claim 7, wherein the upperportion has a concave inner surface overlapping the looped segment andthe opening.
 9. The ophthalmic surgical instrument according to claim 1,wherein the opening has a length that is less than about half of alength of the cutting segment when the cutting segment is in the dilatedconfiguration.
 10. The ophthalmic surgical instrument according to claim9, wherein a majority of the length of the cutting segment is disposedout of alignment with the opening when the cutting segment is in thedilated configuration.
 11. An ophthalmic surgical instrument forsevering a lens of an eye, comprising: a handle; an elongated shaftextending distally from the handle and including a distal end portiondefining an opening, the distal end portion being angled relative to aproximal portion of the elongated shaft that is disposed proximally ofthe distal end portion; and a snare operably coupled to the housing andincluding a looped segment configured to move between a contractedconfiguration and a dilated configuration, in which the looped segmentassumes a diameter approximating a diameter and shape of a lens, whereinthe looped segment is configured to sever the lens upon moving towardthe contracted configuration, wherein the distal end portion has abottom portion configured to be oriented toward a human eye, and anupper portion, the bottom portion defining the opening therein, theupper portion having a concave inner surface overlapping the loopedsegment and the opening.
 12. The ophthalmic surgical instrumentaccording to claim 11, wherein the distal end portion is bent relativeto the proximal portion.
 13. The ophthalmic surgical instrumentaccording to claim 11, wherein the proximal portion includes: a proximalend portion coupled to the handle; and an intermediate portion disposedbetween and interconnecting the proximal end portion and the distal endportion.
 14. The ophthalmic surgical instrument according to claim 13,wherein the distal end portion is bent relative to the intermediateportion.
 15. The ophthalmic surgical instrument according to claim 14,wherein the intermediate portion is bent relative to the proximal endportion in an opposite direction as the distal end portion is bentrelative to the intermediate portion.
 16. The ophthalmic surgicalinstrument according to claim 11, wherein the opening has a length thatis less than about half of a length of the looped segment when thelooped segment is in the dilated configuration.
 17. The ophthalmicsurgical instrument according to claim 11, wherein a majority of thelength of the looped segment is disposed out of alignment with theopening when the looped segment is in the dilated configuration.